1. Povetkin has ducked Wlad in 3 different instances. In 2 of them he even no showed to a press conference. 2. Valuev ducked Vitali and retired 3. David Haye before he faced Wlad consistently ducked Vitali 4. Both Mayweather and Pacquiao 5. The entire middleweight division vs Golovkin
Mayweather ducking Pacquiao is one of the biggest ducks in recent history Mayweather ducking Canelo Mayweather ducking a strong 147 division by "retiring" Vitali ducking Haye Martinez ducking Golovkin
Dempsey ducked Wills Leonard ducked Pryor Old George ducked everybody Bowe ducked Lennox Calzaghe ducked everybody Mosley ducked Mayweather Mayweather ducked Mosley Kessler ducked Green Dirrell ducked Ward Pacquiao ducked Cotto Ioka ducked Cuello Adamek ducked Pulev blah blah blah... Judge 'em by who they fight, not by who they didn't. A whole bunch of people would agree with all of my above list, and if they didn't they would be hypocrites in some way or another for having previously accused someone else of ducking by the same situation.
One could say: "He refused to budge from his demands of a 150 pound catch weight in their negotiations for a rematch to take place in the first part of 2012. Everything was agreed to except Pacquiao's refusal to go up to the full 154 pounds. Pac then signed on to fight 140 pound champion Timothy Bradley."